The present invention relates, in general, to electric power service apparatus for controlling the supply of electrical power to homes and buildings and, more specifically, to watthour meters and watthour meter socket adapters mountable in watthour meter sockets at homes and buildings.
Electrical power is supplied to an individual site by external electrical power line conductors located above or below ground. In a conventional arrangement, electrical power line conductors are connected to contacts in a watthour meter socket mounted on a building wall. Electrical load conductors are connected to another set of contacts in the meter socket and extend to an electrical distribution network in the building. A watthour meter is connected into the contacts in the meter socket to measure the electric power drawn through the load conductors.
Due to the current trend toward the use of plug-in watthour meters, extender type socket adapters have been devised which allow the addition of equipment and features not originally intended for the electrical service. Such watthour meter socket adapters have been constructed as service limiting adapters and provided with power disconnect devices, such as circuit breakers or ground fault circuit interrupters, both for protecting the electrical""service as well as, in certain applications, to limit the amount of power supplied to the use site.
It is common in the electrical utility industry to frequently disconnect electrical service to a particular site. Such service disconnection can be for non-payment, seasonal usage, or rental units in high turnaround areas, such as college campuses, mobile home parks and apartments, etc. Typically, when it is desired to disconnect electrical service to a particular user site, a utility serviceperson goes to the particular site and removes the watthour meter. Another serviceperson must be sent out to re-install a watthour meter to reconnect service to the site. This sequence is labor intensive and, therefore, expensive.
Certain watthour meter sockets are provided with a hand-operated, clamp jaw bypass mechanism which enable a utility to easily bypass the meter by connecting the line conductors directly to the load conductors while the meter is removed for servicing or replacement. The lever clamp bypass mechanism includes a pivotal lever mounted within the socket housing. The lever moves jumpers or bypass conductors between a first position, when the lever is in a downward extending position, in which the bypass conductors are spaced from one pair of the line and load contacts and a second position, when the lever is in an upward extending direction providing a jumper or bypass path between one pair of line and load jaw contacts in the socket. The lever and jaw mechanism may also be provided with or be operative with a jaw clamp device, such as a spring loaded portion of the jaw contacts which securely bias the blade terminals of a watthour meter or meter socket adapter in the socket jaw contacts when the lever is in the first or down position and holds the jaw parts spaced apart when the lever is in the up position for removal or insertion of the meter from or into the jaw contacts.
The bypass jumpers are designed only to bypass the meter while testing or replacement of the meter takes place. The bypass jumpers are not designed to disconnect a load or to reconnect a load in the socket. Indeed, watthour meter sockets typically include a printed label which provides a warning not to use the bypass contacts to disconnect a load.
To properly disconnect a meter service, the main disconnect device must switch the load off. This switch, however, is not always accessible to the utility service person as it is usually mounted in a fuse or circuit breaker box inside of the building. Since the utility may be disconnecting the meter service when the power bill has not been paid, the customer will not usually cooperate with the utility service person and turn the power off himself. If the bypass jumpers are used to disconnect or reconnect the load, an arc can be generated between the jaw contacts and the bypass jumpers causing injury to the utility service person.
For safety purposes, primarily to prevent the watthour meter from being reinstalled into the socket jaw contacts when a load is connected to the load conductors in the building or home which receives power from the socket, a multi-step installation procedure has been developed and essentially has become a utility industry standard.
If the watthour meter is installed in the socket when the load conductors connected to the socket are connected to an active load in the home or building, arcing will occur between the meter blade terminals and the socket jaw contacts. Arcing creates an explosive event and gases, which are propelled out of the socket toward the utility serviceman, pose a significant injury potential to the utility serviceperson, as well as a fire hazard.
A prior art meter replacement and reinstallation procedure in a socket having a lever controlled set of jaw bypass contacts uses a conventional socket adapter base having internally mounted jaw contacts connected to blade terminals which project outwardly from the bottom wall of the base for engagement with the socket jaw contacts. The base jaw contacts receive mating blade terminals mounted on a similar base attached to the rear surface of a generally rectangular housing shown in FIG. 1. A one phase, two phase or three phase disconnect switch, having an externally movable lever, is mounted in the housing and has contacts connected between the housing base blade terminals. A handle is mounted on the top of the housing to facilitate installation and removal of the housing with the socket adapter base.
When a watthour meter is to be removed from the socket, the socket mounted bypass lever is moved to the up position. This disengages the blade clamping force from the socket jaw contacts, enabling the meter blade terminals to be easily removed from the socket jaw contacts, and at the same time, closes or electrically connects the bypass jumpers and the jaw contacts.
After the watthour meter has been removed from the socket, the disconnect housing is mounted in the socket adapter base, with the disconnect switch in the xe2x80x9cONxe2x80x9d or current carrying position, to provide a closed circuit between the line and load jaw blades in the socket adapter base. The socket adapter base is then mounted in engagement with the socket jaw contacts. The bypass lever is then moved to the down position to open the bypass contacts and to clamp the base blades in the socket jaw contacts. Next, the disconnect switch is moved to the xe2x80x9coffxe2x80x9d position and the disconnect housing removed from the socket adapter base. The socket cover and a bladed adapter cover are then mounted to the socket. Lastly, a sealing ring in the case of a ring style socket is then mounted on the socket to seal off the socket and to complete the removal of a watthour meter from the socket.
When it is desired to reconnect a watthour meter in the socket, a reverse sequence is employed. The sealing ring, the socket cover and the adapter cover are first removed from the socket. With the disconnect switch in the xe2x80x9cOFFxe2x80x9d position, the disconnect housing is urged into engagement into the socket adapter base in the socket. The disconnect switch in the disconnect housing is the moved to the xe2x80x9cONxe2x80x9d position.
The socket bypass lever is then moved to the up position bringing the bypass contacts into engagement with the socket jaw contacts. Since the disconnect switch had previously been moved to the xe2x80x9cONxe2x80x9d position, any potential arcing caused by the slow, manual movement of the bypass contacts into engagement with the socket jaw contacts under an active load is prevented by tripping of the disconnect switch.
With the bypass jumpers engaged with the jaw contacts, both the disconnect housing and the adapter base can be removed from the socket. The watthour meter may then be easily installed into the non-clamped, socket jaw contacts. Next, the bypass lever is moved to the down position removing the bypass contacts from engagement with the socket jaw contacts and allowing the clamp jaw portions to move into secure, biased engagement with the meter blade terminals to securely hold the watthour meter in the socket. Finally, a socket cover and seal are used, as required.
Prior watthour meter bypass disconnects have been provided with printed instructions, usually on a separate card which specify the sequence of operation to remove a meter and to install the bypass disconnect in the socket. However, these devices did not provide both meter disconnect and meter reconnect sequences in a readily visible location for use by any utility service person without requiring a separate instruction card.
Prior meter disconnects have also been provided with lights, typically one for each load phase, which indicate if power is supplied to a load even though the disconnect switch is in the xe2x80x9coffxe2x80x9d position. Reconnecting a watthour meter into an active load creates the potential for dangerous arcing of the bypass contacts which are not designed to handle instantaneous high currents. However, when using such prior meter disconnect devices, it is up to the utility service person to remember to check the state of the lights at the prior sequence step during the meter disconnect and reconnect operations.
While this procedure and equipment, if properly used, minimizes the possibility of arcing and the explosive generation of gases which could damage the socket as well as possibly injure the service utility person, it is not without certain disadvantages. One problem is that the socket adapter base is not always clamped securely in the socket jaws when the socket bypass lever is moved to the down position during meter disconnect. If this occurs, the socket adapter base has a tendency to pull out of the socket with removal of the disconnect housing from the socket. It is then oftentimes difficult to separate the disconnect housing from the socket adapter base.
Another problem involves the handle on the disconnect housing, which has heretofore been mounted on the top of the housing. Installation and removal forces exerted on the disconnect housing through the handle have a tendency to be applied more through the top portion of the housing and not equally or directed across the front entire housing. This can lead to less than complete engagement of the disconnect housing blades in the socket adapter base jaw contacts.
Since the handle on the prior art disconnect housing has been mounted on top of the housing, the disconnect switch lever sticks out of the front of the housing. This places the disconnect switch lever in a position susceptible to damage during storage and transport of the disconnect housing to and from utility sites.
Thus, it would be desirable to provide a disconnect watthour meter socket adapter which facilitates easy removal and reinstallation of a watthour meter into and out of a watthour meter socket while minimizing the potential for injury to the utility serviceperson and damage to the watthour meter socket or disconnect if the bypass contacts are reconnected under load. It would also be desirable to provide a disconnect watthour meter socket adapter which is capable of diverting arcing gases generated during a meter disconnect or reinstallation away from the utility serviceperson to minimize the potential for injury to the utility serviceperson. It would also be desirable to provide a disconnect watthour meter socket adapter which has a more centralized mounting position of the handle for ease of removal of the disconnect housing from the socket adapter and even mounting force on the disconnect housing in the socket during a meter reconnect procedure. It would also be desirable to provide a disconnect watthour meter socket adapter which protects the disconnect switch lever from contact with external objects so as to minimize the potential for damage to the disconnect switch lever.
The present invention is an electrical service apparatus in the form of a disconnect watthour meter socket adapter which facilitates the disconnection and reinstallation of a watthour meter into and out of a watthour meter socket.
In one aspect of the invention, an electrical service apparatus is mountable in an electrical socket having jaw contacts connected to electrical power line conductors and load distribution conductors. The apparatus includes a housing having a base, and an annular sidewall extending from the base. An electrical disconnect switch is mounted in the housing and has switchable contacts to selectively connect and disconnect the line conductors from the load conductors in the meter socket. A plurality of electrically conductive connectors are mounted through the base and have a first end extending outward from the base adapted for connection to the socket jaw contacts, and an opposed second end connectable to the electrical disconnect switch.
In another aspect of the invention, the electrical connectors are preferably in the form of rigid bus bars. This enables the connectors to fixedly support the disconnect switch in the housing without the need for additional fasteners or supports.
A cover is mounted on one end of the sidewall of the housing. An aperture is formed in the cover to open access to the movable lever on the disconnect switch.
In another aspect of the invention, at least one aperture is formed between the cover and the sidewall of the housing to permit gases caused by arcing of the bypass contacts in the socket from the housing and externally of the cover. In a specific aspect, a plurality of apertures formed between a plurality of radially extending, circumferentially-spaced ribs carried on the cover and engagable with one end of the sidewall of the housing. Preferably, a peripheral lip extends from the cover toward the base of the housing to direct gas flow through the apertures away from the cover and toward the base of the housing.
A primary handle is fixedly mounted to the housing. Preferably, the primary handle is mounted over a central lateral axis of the cover. The primary handle includes two spaced legs fixedly engaged on one end to the cover and a central leg extending between another end of the side legs and spaced from the cover. Preferably, the central legs are disposed over the disconnect switch lever as a protective shield.
In another aspect of the invention, the apparatus includes an ejector handle mounted for movement between first and second positions with respect to the cover. Ejector arms are connected to the ejector handle and extend through the cover and the housing to distal ends disposed exteriorly of the base of the housing. The distal ends of the ejector arms are movable with respect to the base of the housing upon movement of the ejector handle from the first position to the second position to separate the base of the housing from an attached, electrical component.
The ejector handle may be provided by itself on the cover or in combination with the primary handle wherein the ejector handle is normally biased to the first position in which a central leg of the ejector handle is spaced from a central leg of the primary handle.
According to another aspect of the present invention, the ejector handle may be used by itself or in combination with the primary handle on the cover or end wall of any socket mounted electrical apparatus, including watthour meters. In this aspect, the ejector handle with or without the primary handle may be mounted directly on the end wall of the apparatus cover, with the ejector arm or arms extending through the cover to distal ends projecting exteriorly of the base of the apparatus to separate the apparatus, such as a watthour meter, from the socket in which it is mounted.
In another aspect, the invention defines a method for removing and remounting an electrical watthour meter in a meter socket having jaw contacts connected to electrical power conductors. The method includes the sequential steps of:
removing a socket cover from a socket housing;
moving a socket contact bypass lever to a position connecting bypass contacts between socket line and load jaw contacts;
removing the watthour meter from the socket;
providing a disconnect housing having an electrical disconnect switch carrying switchable contacts connected to a plurality of connectors extending externally of the housing for connection to the socket jaw contacts;
moving an electrical disconnect switch control lever to a position placing the disconnect switch contacts in a closed position;
installing the disconnect housing in a base having jaw contacts receiving the external ends of the connectors on the disconnect housing and external terminals adapted to be engaged with the socket jaw contacts;
installing the disconnect housing and the base into the socket;
moving the socket contact bypass lever to a position moving the bypass contacts to an open position from the socket jaw contacts;
switching the electrical disconnect switch control lever to an off position opening the switchable contacts;
verifying that potential lights carried on the housing are all off, and
removing the housing from the base.
In another aspect, the inventive method further includes the steps of replacing the socket cover on the socket housing; and
installing a meter opening cover on the socket cover.
The method also includes the steps of reconnecting a watthour meter in a meter socket comprising the steps of:
verifying that a main disconnect in the load distribution network is in an off position;
removing the meter opening cover and the socket cover from the socket housing;
with the disconnect switch control lever in the off position, mounting the housing in the base in the socket;
verifying that the load side potential lights are off;
switching the disconnect switch control lever to the on position;
moving the socket contact bypass lever to a closed position closing socket bypass contacts to connect the socket line contacts to the socket load contacts;
removing the housing and the base from the socket;
installing a watthour meter in the socket jaw contacts;
moving the socket contact bypass to a position disconnecting the socket bypass contacts from the socket jaw contacts; and
replacing the socket cover.
The present invention provides several advantages over previously devised electrical apparatus using a disconnect switch for meter disconnection and reconnecting. First, the gas apertures or ports formed between the cover and the sidewall of the adapter housing uniquely provide an escape gas flow path for arcing gases generated if the bypass contacts are moved to a closed position while an active load is connected to the load conductors. The arc gasses are directed away from the cover toward the base of the housing, thereby minimizing the potential for injury to the utility serviceperson normally positioned in close proximity to and facing the cover.
The present invention also provides the rigid bus bar connectors to both electrically connect the switchable contacts of the disconnect switch to the socket jaw contacts in the socket and, also, to fixedly mount the disconnect switch within the housing without the need for additional fasteners. This simplifies assembly of the present apparatus and reduces material and assembly costs.
Further, the present apparatus includes a laterally centrally located handle which centralizes insertion and pullout forces through the handle on the socket adapter. This reduces the magnitude of push-in or pullout force required to install or remove the disconnect switch adapter in a meter socket.
The present apparatus also includes a unique ejector handle, usable by itself or in combination with the primary handle. The ejector handle includes movable ejector arms which are extendable from the base of the adapter housing to assist in separating the adapter housing from an attached electrical component, such as a socket mounting base used during the meter disconnect and reconnect sequence.